The IL-13 receptor structure differs on various cell types and may share more than one component with IL-4 receptor.
The IL-13 receptor structure differs on various cell types and may share more than one component with IL-4 receptor.
复制标题
IL-13 受体结构在不同细胞类型上有所不同，并且可能与 IL-4 受体共享不止一种成分。
作者：
N. Obiri;P. Leland;T. Murata;W. Debinski;R. Puri
我们已经报道了IL-13 R的表达和特征，并且已经证明在某些细胞类型上，IL-13竞争IL-4结合，而IL-4不竞争IL-13结合。基于这些观察，以及IL-13和IL-4交联蛋白的大小，我们得出结论，IL-13的受体是复杂的，并且与IL-4的受体共享一个亚基。为了探索IL-13 R的复杂性，检测了多种细胞类型的IL-13和IL-4结合。我们在这项工作中报告说，IL-4并不总是很好地结合细胞，结合IL-13，但反过来也是如此。我们还发现IL-4可以比IL-13本身更有效地竞争IL-13结合。交联研究支持这些观察结果，并表明，125 I标记的IL-13只结合到一个单一的65- 70 kDa的蛋白质在MA-RCC和U251细胞，而在TF-1细胞中，它交联到两个膜蛋白的65 - 70 kDa和140 kDa。此外，通过使用由IL-13和假单胞菌外毒素A组成的嵌合蛋白，我们观察到IL-4通过阻断两种细胞因子受体的共同形式来中和IL-13毒素对COS-7细胞的细胞毒性。我们认为，65- 70-kDa形式的IL-13 R是IL-13和IL-4 R之间共享的主要共同组分。然而，在某些细胞类型中，初级IL-4结合（p140）蛋白也参与IL-13 R复合物的形成。此外，γ（c）或另一种相互作用亚基可影响IL-13与其受体复合物的结合。因此，我们提出至少有四种形式的IL-13 R。
We have reported on the expression and characteristics of IL-13R and have demonstrated that IL-13 competes for IL-4 binding while IL-4 did not compete for the IL-13 binding on some cell types. Based on these observations, and the size of IL-13 and IL-4 cross-linked proteins, we concluded that the receptor for IL-13 is complex and shares a subunit with the receptor for IL-4. To explore the complexity of the IL-13R, a wide variety of cell types was examined for IL-13 and IL-4 binding. We report in this work that IL-4 does not always bind well to cells that bind IL-13, but the reverse is also true. We also found that IL-4 can compete more effectively for IL-13 binding than IL-13 itself. Cross-linking studies support these observations and demonstrate that 125I-labeled IL-13 bound exclusively to a single 65- to 70-kDa protein in MA-RCC and U251 cells, while in TF-1 cells it cross-linked to two membrane proteins of 65 to 70 kDa and 140 kDa. Furthermore, by using a chimeric protein composed of IL-13 and Pseudomonas exotoxin A, we observed that IL-4 neutralized the cytotoxicity of the IL-13 toxin on COS-7 cells by blocking a common form of the two cytokine receptors. We propose that the 65- to 70-kDa form of the IL-13R is the predominant common component shared between IL-13 and IL-4R. However, the primary IL-4 binding (p140) protein also participates in the formation of the IL-13R complex in some cell types. In addition, the gamma(c) or another interactive subunit may influence IL-13 binding to its receptor complex. Thus, we propose that there are at least four forms of IL-13R.